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By Y. P. Malhotra, JE. C. Carter

"Syncrude's overburden removal requirement ranges from 20 million to 30 million bank cubic metres per year to meet tarsand demands for the production of 129,000 barrels of synthetic crude oil per day. The economic tar-sand lies beneath a variable thickness of overburden materials, composed of silts, clays, some sands of lacustrine origin, wind-deposited sand dunes, and out-wash sands and gravels.For the removal of overburden, Syncrude commissioned its own mobile equipment fleet in January 1981. This fleet consists of two Demag 241 hydraulic shovels, ten Titan 33-15B trucks and support equipment. Prior to this, all overburden removal was being carried out by contractors.This paper presents an overview of overburden removal at Syncrude, with particular reference to the performance of its own fleet.IntroductionThe Syncrude Tar Sands Plant was officially opened on September 15, 1978. After an expenditure of approximately $2.26 billion, the second and the largest commercial tarsands plant was on stream toward a permit production rate of 129,400 barrels of synthetic crude oil per day. The Syncrude Plant, a joint venture of six oil companies, the federal government and the Alberta government, is a major step forward toward the goal of Canadian energy self-sufficiency.The Mildred Lake operation of Syncrude Canada Ltd. Is located 40 km north of Fort McMurray and 480 km northeast of Edmonton in the Province o f Alberta.Synthetic crude oil leaving the plant is a blend of two-third s gas oil and one-third naphtha. The two streams combine in a pipeline and flow to Edmonton. The product takes six days to make the journey, arriving at four locations in the city Imperial's Strathcona Refinery, Gulf's Edmonton Refinery, the Interprovincial pipeline terminal and the Trans-Mountain pipeline terminal. Each Syncrude owner receives a share of oil equal; to its percentage of ownership in the project. At the present time, the oil is being utilized by Canadian refineries from Vancouver to Montreal."

Jan 1, 1983

By C. M. Davidson, D. J. Drexler

"Sulphuric acid treated with hydrogen peroxide to destroy organic contaminants could conceivably show increased corrosivity toward carbon steel shipping and storage vessels, caused by the persistence of a peroxide residual. This paper describes work performed to determine the effect of 0-200ppm hydrogen peroxide on the corrosion of carbon steel by 93% and 98% sulphuric acid at room temperature (23ºC) and 50ºC.Steel electrodes were exposed to acid containing several peroxide levels (0. 45, iOO and 200 ppm) for up to two weeks. Specimens were removed at intervals and weight loss, open circuit potential, depth of metal loss and residual peroxide concentration recorded.Hydrogen peroxide decomposes considerably over two weeks in iron-contaminated sulphuric acid. initial peroxide concentrations > l00 ppm suppress corrosion, but the effect is lost when concentration decays below about 60 ppm. Sustained peroxide levels in the range below 60 ppm may increase corrosion rates. These phenomena are interpreted by analogy with anodic passivation."

Jan 1, 1987

By Zdenek D. Hora

British Columbia is an important producer of a variety of industrial minerals for both domestic and export markets. Some commodities such as limestone, dolomite, gypsum, calcium carbonate, silica, barite and magnetite are raw materials for well-established industries located in British Columbia, Alberta and northwestern USA. Others, like magnesite, sulphur, jade, asbestos, dimension stone and clay products, are mainly exported in processed form to overseas customers. Companies are developing markets for relatively new mineral products, including pumice, volcanic cinder and zeolites. A number of attractive geological targets have been identified by industry while research by government geologists has outlined the potential for refractory minerals, gemstones, garnet, nepheline syenite, carbonatites, residual kaolin, igneous apatite and peat.

Jan 1, 2001

By Jessica Egan, Daniel Hodouin, Mohammed Reza Khalezi, Steve Bellec, Claude Bazin, Carl Duchesne

"A model for gold leaching was developed and implemented into a simulator. The simulator uses a description of the ore that is based on the mineral composition and precious metal content. The model accounts for the distribution of minerals and precious metals through the size intervals. An ore texture model based on precious metals and minerals grain sizes within the ore is used to predict the exposed surface of the species in the various size intervals. A model is proposed to predict the rate of dissolution of any species dissolution using the exposed surface, particle size, cyanide and oxygen concentrations, temperature, pH and agitation. The flow of slurry through a leaching tank is modelled using a parallel arrangement of perfect mixers to simulate a bypass and a Cholette-Cloutier mixer model. The simulator can be used for circuit optimization but was developed to provide an environment for learning the basic concepts of process analysis methods. Examples are given to illustrate the application of the simulator for planning tracer tests and sampling campaigns.INTRODUCTIONThe constant pressure to improve the operation of processes that are already close to optimum imposes to plant engineers to be aware of the available process analysis tools and to be able to use them to assess process operation and make a diagnosis to possible problems. Some of these tools are:•,Sampling the streams of a process;•,Data reconciliation;•,Analysis of mixing in reactors;•,Estimation of rate parameters;•,Optimal tuning and flow sheet modification;•,Automatic control and real time optimization.Although some of these tools are part of the curriculum of many university engineering programs, the students are not exposed to actual process analysis problems. In addition the complexity of the ore dressing processes compounded with unavoidable measurement errors and plant disturbances can discourage many motivated engineers. These factors often lead to an incomplete valorization of the collected data and a poor return on the investment associated with the sampling, testing and analysis of the samples.Simulators are readily available for process optimization (Yalcin and Shang, 2006) by allowing:•,The simulation of various flow sheet configurations;•,The simulation of a change of operating conditions;•,The simulation of various control strategies;•,The training of plant operators.However few simulators have been developed with the objective of providing an environment for training plant engineers and technicians to the use of tools for process analysis and optimisation."

Jan 1, 2008

By Carol J. Odell

As a mining social practitioner, social indicators are within the purview of required competencies. A situation, where the ER manager requested assistance in quickly deriving a few social indicators for the strategic plan motivates this paper: despite ample technical knowledge about indicators, a clear understanding of stakeholder aspirations and concerns, as well as familiarity with management priorities such a request required reflection to produce a satisfactory approach, which combined pragmatism with enough academic rigour to provide reliable measures, while being justifiable to management who are unfamiliar with many of the pertinent debates. Importance: Social indicators enable the identification of more and less effective mine-community engagement strategies as well as providing primary data to better understand how the mine-community social system responds to different interventions, thus guiding future engagement plans. In addition social indicators: ? Assist communication about social strategies with Engineering and Operations management, using a quantitative language that is familiar to them. ? Provides concrete data to engage stakeholders to discuss progress and challenges arising, to move discussions towards technically robust strategies and away from politically interested proposals. ? Finally, social measurement is required more and more in due diligence, covenants and ongoing monitoring in Independent Engineering assessments of projects for financing. This paper begins by considering some technical considerations that are useful to guide indicator development. It then introduces the field research informing this paper and discusses some useful results in the light of further applicable concepts from the literature. The paper ends by considering corporate aims in applying corporate social responsibility (CSR) programs and discusses the application of the research for practitioners at mining operations, in the light of these aims.

May 1, 2010

By G. Barbery

"Particle composition distribution is an essential feature of materials processed by physical separation methods. The amenability to segregate a feed material in a concentrate and a tailings stream depends to a large extent on what is called usually the ""liberation"" of the various mineral phases that are present in an ore. In fact the energy consumed in crushing and grinding has the major justification of producing particles that are as close as possible to monominerallic. Monophasic particles are able to reveal physical differences in mineral properties that make their separation possible. For many years, various authors have insisted on the concept of liberation, without noting that, in practice, it can be a pure concept which does not lead to measurements or predictions. The present paper insists on the concept of particle composition distribution, in which the complete distribution is the information to be obtained, and not the ""liberation·· of various phases, just like for particle size distribution, the complete distribution is an objective commonly desired, and not one or two values representing the coarse or fine fraction.2. NOTATIONS-EQUATIONSFor the purpose of the paper, a particle will be characterized by its volume Vp, and its volumetric composition with respect to a mineral of interest, which will be given the notation ""O"". All the other minerals present will be called ""1"". This notation does not imply that the particles are biphasic, but that we are interested in the composition of particles with respect to one phase only. The volumetric composition will be given the sybol m:"

Jan 1, 1986

By G. A. Mallory

"The South Bay Division of Selco Mining is located fifty-four miles northeast of Ear Falls Ontario on Confederation Lake. The concentrator operates five days a week and processes six hundred tons per day of copper zinc silver sulphide ore. The concentrator is comprised of crushing, grinding, differential flotation, thickening and drying circuits. The major constituents of the concentrator feed are: chalcopyrite 7%, sphalerite 20%, pyrrhotite 3%, pyrite 25 - 30% and felsitic volcanics 40 - 50%. The mine went into production in March 1971 with an anticipated three year life and is now scheduled for closure in the summer of 1981. Recent mine production has been limited to three cut and fill stopes which have widely varying ore grades, therefore mill feeds vary from 0.25 to 4% copper, 3.5 to 27% zinc, 0 to 0.4% lead and 15 to 30% iron.In mid 1977 Selco negotiated a six month rental purchase agreement with Outokumpu Instruments Canada Limited for a five stream analyser system. The Minexan 202 probes were the first Outokumpu probe type analysers installed in Canada although Outokumpus' Courier systems are well known. Installation of the system took place in April 1978 and after numerous hardware faults the six month evaluation began in August. By December it was obvious that the Minexan 202 probes with proportional detectors did not have adequate resolution to determine low copper values in either of the tailings streams. Outokumpu offered to replace the tailings analysers with a new prototype solid state detector probe the following summer. The evaluation on the five Minexan 202 probes continued until August 1979 when the new solid probe was installed. The Minexan S (solid state) probe was evaluated with the three remaining Minexan 202 probes until December 1979 when Selco elected to purchase the system."

Jan 1, 1981

By J. Dong

"Xanthate is a sulfide collector that has been widely used in flotation for almost a century. It is inexpensive, easy to synthesize and apply, and produces good metallurgy in the right applications. However, a major drawback of xanthate is that it decomposes easily and generates CS2 gas in transportation, storage and operation, which can be harmful to human health. Also, excessive xanthate in tailings pond leads to toxicity of the process water and potential damages to aqua-life systems. New regulations in Ontario require that the TWA (time-weighted-average) value of CS2 in the work place is below 1 ppm, which is 1/10 of the previous limit. The stringent regulation may eventually sweep other regions of Canada with the increased awareness of healthy working conditions and environment protection. Therefore, it becomes very important to find xanthate replacements which will be “green”, i.e., environmentally friendly.In this research work, a systematic procedure is used for collector evaluation using the Sudbury nickel sulfide ores from Vale’s Ontario operations, starting with the collector properties (MSDS) evaluation, followed by batch flotation tests, miniplant tests, plant trials and economic evaluation. It is found that the most promising xanthate replacement is dithiocarbamate.INTRODUCTIONSulfide mineral flotation has been practiced since the early 20th century. Its industrial importance is well recognized as mineral concentrates from flotation can be economically smelted and refined to provide primary metals. Collectors play a vital role in froth flotation. There are reagents possessing both a polar group that binds them to the mineral surface and a nonpolar group that is oriented away from the surface to attach air bubbles. The introduction of xanthate as a sulfide collector in 1925 was a remarkable development in froth flotation (Keller, 1925). It is low cost, easy to synthesize, water soluble, simple to control in application. Most importantly, it has strong capability and usually good selectivity for sulfide mineral flotation, which have been keeping its application prominent for almost a century."

Jan 1, 2011

By S. W. Stogran

"Chemical and limited biological monitoring of mine and mill effluents are being used by regulatory agencies to monitor and control discharges to the environment. Amendments to the Federal Fisheries Act may make it mandatory for mines to conduct Environmental Effects Monitoring (EEM) which will change the emphasis from monitoring effluents to monitoring impacts on receiving waters. The EEM amendments may expand the scope of present environmental studies to include: effluent mixing zone delineation; inventory and classification of resource, habitat, and historical receiving environment; effluent quality determination; chronic and acute bioassay testing; tissue analysis; benthic invertebrate monitoring; fish population surveying; fish tainting evaluation; and the evaluation of impacts on fish habitat, invertebrate communities and fisheries resources. The requirements for EEM have not yet been worked out by the mining industry and the government committee. Experience at Lakefield Research in conducting biological monitoring studies for the mining industry has shown that biological monitoring may be useful for assessing environmental impacts only if programs are planned and executed to collect relevant data, thus minimizing costs and maximizing effectiveness.IntroductionThe chemical monitoring of effluents and water bodies receiving effluents is common practice in the Canadian mining industry and has been used routinely by regulatory agencies to control discharges to the environment. Biological monitoring has also been used on a limited basis, primarily to augment chemical data collected. A number of regulatory bodies, primarily in Canada and the United States, have been incorporating biological monitoring into environmental regulations.Various forms of biological monitoring techniques have been used in Canada and the United States to help assess the impact of mining operations and effluents on the environment. Biological monitoring includes a wide range of activities, from monitoring metal uptake in individual organisms to examining the population dynamics in ecosystems. The most commonly employed biological monitoring techniques are the chronic lethality toxicity tests. Also becoming widely used are in situ and chronic toxicity tests."

Jan 1, 1994

By Christian Ottergren

"Modern crushers offer double the capacity and performance of classic models. In some cases crushers are replacing SAG circuits, the advantages being smaller investment and lower operating costs. Is Tertiary crushing replacing SAG milling as the most optimal grinding method? Does tertiary crushing achieve the same outcomes as SAG milling? This paper considers these questions and provides an assessment of the strengths of tertiary crushing in comparison to other methods. Two case studies: a Scandinavian Platinum Project, and CODELCO, are also presented.INTRODUCTIONResearch on basic parameters in crushing started at Chalmers University in 1993. The initial project has developed and now involves several related areas. Modelling in accordance with new theories has resulted in modified designs which have been implemented and shown improved performance at operating mines in Chile. Sandvik Rock Processing is a partner and a major supporter of this program. This paper will cover some of the achievements and give references to the research reports.The mining industry has for many years mainly used crushers of the traditional 7’crusher concept, with thread adjustment of the setting and with a spring or hydraulic overload system. This machine type has been the workhorse for crushing throughout the world. The explanation for the dominance of this machine is that it has a reliable mechanical design. It can be estimated that about 2000 crushers of this design are still at work.Technical development in all fields utilizes new technologies like high-strength materials, advanced control systems and more extensive use of hydraulics. This is the reason why today’s motorcars, for example, are more efficient, more reliable and more environmentally friendly than their predecessors in the 1950s. Crushers are no exception. This paper will cover experience from the latest-generation cone crushers developed by Sandvik Rock Processing.The parts in this paper related to the CODELCO ElTeniente copper mine in Chile are coauthored with responsible personnel from the operation at the mine."

Jan 1, 2004

By Terry Braden

"Meeting probable world mineral demand in the years ahead will almost certainly require an ability to economically treat lower grade and more complex ores. Achieving this will require extensive research and technical development across the full spectrum of mineral processing.For mid-sized or smaller companies the most effective way to participate in such extensive programs - and gain access to the technology required to stay competitive - may be through collaborative research.This paper explores the recent history of collaborative research in mineral processing and in particular its ability to attract world-class multi-institutional research teams with sufficient resources to make step-change advances. It chronicles the advances achieved, but also explores the research architecture and administrative structures required to deliver research outcomes and technology transfer mechanisms to a range of often disparate sponsoring companies.INTRODUCTIONIn medieval times the dream of alchemists was to turn base metals into gold. We modern alchemists, of course, don’t waste our time on that sort of foolishness: we turn base metals into dollars. When I see the profit reports filed by some companies recently, I can only conclude that a lot of those present today must be pretty good at this.But the fact that we are here at this conference reminds us that an alchemist’s work is never done; turning base metals into dollars is not a one-trick wonder but an art that we must extensively refine year after year if we are to survive in a competitive marketplace.It is not that demand for metals is likely to slow; most people seem to think that China, India, Brazil and other emerging economies are still at the lower end of their demand curve. They will need significantly larger volumes of metals in the years ahead. The challenge for us as processors is that to supply increasing tonnages of those metals profitably we will almost certainly need to process more complex or lower grade ores and probably to do so with reduced energy inputs."

Jan 1, 2009

By J. A. Abols, P. M. Grady

Recovery via gravity is one of the oldest mineral processing methods available. Unfortunately, the use of gravity techniques for gold recovery has been in decline for the past century as more effective chemical processes such as flotation and leach/CIP have been developed. Recently, with the push towards more sustainable environmental outcomes, the benefits of gravity separation have become more apparent. While gravity as a unit process is not usually capable of achieving as high a recovery as flotation or whole ore cyanidation, a combination of gravity devices alone or in conjunction with these processes can offer significant advantages to the operator. This paper reviews the range of gravity devices available, their application and the results that can be achieved by maximizing gravity through the use of a combination of gravity recovery devices. Three case studies are provided.

Jan 1, 2005

By Jonas Olsson

"The picture of China as an antiquated continent is changing rapidly and fast-forwarding progress is a fact in most infrastructural fields. Mining is not an exception. China is today the largest producer of aluminum, coal, steel, zinc, tin, lead and manganese and the country’s mineral resources comprising approximately 12% of the global reserves ranks them number three in the world after US and Russia.In order to feed the growth industry is needed to take extra ordinary strides to improve supply of raw material and Chinese mines are continuously being upgraded with the latest western technology to meet the increasing domestic demand of base metals.In Anshan located in China’s northeast province Liaoning we find one of the fastest developing mining companies, Angang Iron & Steel Group Co. Ltd. With their six mines that together process approximately 60 M ton iron ore/year Angang Iron & Steel Group Co. Ltd is the largest iron ore company in China. The group’s thorough pre-studies and technical evaluations over the past five years have made them very successful in both plant upgrades of existing operations and green field projects.INTRODUCTIONWe live in a time when the world market is gradually acclimatising to the global consequences of “The China effect”. An effect caused by a formerly sleeping giant nation that during the last years has awakened and developed beyond comparison, primarily because of booming infrastructure projects and demand for capital and consumer goods"

Jan 1, 2006

By Gunnar Nord

Introduction ??Atlas Copco has customers both amongst Miners and Contractors ??We believe that the contractor's approach to tunnelling is worthstudying ??For a tunnel contractor the incentive is speed as ?30 % of the costs are material related ?70 % of the cost are time related ?A tunnel contractor favours utilizing of the face ?A miner favours utilizing of the gear ??Statement; In mining, a long term average advance rate of more than 10 m / day can be achieved with the excavation techniques availabletoday

May 1, 2009

By T. R. Roy

"This paper presents an objective model for the estimation of fire risk potential of an underground coal mine panel by the bord-and-pillar method of mining where extraction is carried out by depillaring with caving. The fire risk rating procedure for the estimation of fire risk potential involved in the panel is described in detail. The model developed thereof is tested with the field data collected from different collieries across the country along with the laboratory data for critical assessment of fitness of the model. Some results showing the validity of the model are also cited here. Introduction The occurrence of fire in underground coal mine panels is quite common in India and elsewhere. These fires cause extensive loss of resources.Although substantial work has already been done by different research organizations, the problem has not been fully eliminated.The causes of panel fires depend not only on the spontaneous heating susceptibility of coal, but also on the extraneous conditions created in the panel due to the mining operations. From the studies done so far by various organizations, it is apparent that two types of parameters associated with spontaneous heating of a coal mine panel exist: intrinsic and extrinsic. Parameters related to the nature of coal, i.e., its physicochemical characteristics, petrographic distribution and mineral make-up are intrinsic, while the extrinsic parameters are related to the atmospheric, geological and mining conditions such as scope of leakage of air into the panel, wetness of mines, heat dissipation capacity of the panel, gassiness of seam, geological disturbances, method of extraction, size of panel, etc.Banerjee (1982) identified twenty-two mine parameters such as spontaneous heating susceptibility of coal, method of mining, geological disturbances, quality of overburden, degree of consolidation of coal mass, scope of accumulation of coal fines, etc. that can influence spontaneous heating in underground mines. He used the terms “high” and “low” for fire risk rating of each of these parameters. Since this approach is oversimplified, it can not determine the exact fire risk potential of an underground working."

Jan 1, 2003

By Bruce Mennie

PT Freeport Indonesia (PTFI) operates copper and gold mining operations in a mountainous area of the Mimika regency, near Tembagapura, Papua (formerly, Irian Jaya), Indonesia. The mining and concentrating operations typically produce 240,000 metric tonnes per day of Copper and Gold ore from the combined mining of an 80,000 tonne per day (ore) block cave operation (DOZ Mine) and a 160,000 tonne per day (ore) open pit mining operation (Grasberg Open Pit). The Grasberg Open pit mine will be complete in 2016 at which time PTFI?s operations will convert to Underground. Mining operations will transition from today?s mixed surface and underground operation to full underground mining over the next 6 years. This paper reviews the history of Redpath?s relationship with PTFI, beginning with a raiseboring contract in 1981 and evolving into vertical and horizontal development contracts of up to 37,700 equivalent metres of lateral development and 4,000 metres of vertical development in 2011. An overview of the current operations (PTFI?s Grasberg Open Pit and DOZ Underground Mines) and transition period (challenges for the transition from current to future underground mines) is presented with details of development of common underground infrastructure and future mines; Big Gossan Mine, DMLZ Mine, Grasberg Block Cave Mine, and the Kucing Liar Mine.

Oct 1, 2010

"As mine head grades decline and orebodies become more complex, traditional mineral processing techniques and flowsheets to achieve saleable concentrate become more difficult to design and construct. Mines with lower quality concentrates or concentrates with penalty elements are particular under threat. The economics of these operations are far more susceptible to metal price, concentrate treatment terms and the availability of other, cleaner concentrates. Additional value may be realised for these orebodies through improved recovery by producing a low grade middling concentrate for further processing, in conjunction with a saleable concentrate.The most cost effective way to reduce impurity levels is to do so as early as possible in the mining value chain. Technologies such as fine grinding and fine particle flotation are well established as effective methods for impurity rejection in mineral processing. What is normally overlooked is how a hydrometallurgical process could also be integrated in the overall flowsheet to achieve higher overall recovery at the mill. In the base metals environment, this is mainly because hydrometallurgical processes are associated with production of metal or use of expensive and toxic precipitating agents once the minerals of interest are solubilised. These processes can be very expensive, particularly with rising power costs and poor economies of scale in capital costs associated with low production rates from middling streams.Glencore Technology (GT) has recent experience in the treatment of middling and low grade concentrate streams as well as tailings streams to compliment a concentrator flowsheet in a refractory gold and base metals setting. The value proposition is the isolation of a low grade middlings concentrate from the primary circuit or the tailings stream for upgrading to an intermediate product with an equal or higher grade than the primary concentrate to allow blending for sale. This allows plants to operate on a more favourable part grade-recovery curve while avoiding the expense of metal production. For existing operations this is particularly attractive since it can be added on with no process interruptions.Two case studies are examined showing flowsheets and costings to arrive at the value proposition of the GT low grade treatment flowsheet."

Jan 1, 2017

Taking Up the AFN Corporate Challenge ?? About MAC ?? ?Towards Sustainable Mining? ??Mining and Aboriginal Peoples Framework ?? AFN-MAC Relationship ?? A New MAC Northern Initiative ??Social and Economic Progress ?? A View to the Future?

May 1, 2009

In 2009 Newmont Mining Corporation?s annual global spend on grinding media reached $94M USD, having doubled in the five years since 2004. The major contributing factor to the spend escalation during this period was unit consumable price, with total media consumption also rising as a function of annual ore tonnes milled. In an effort to better understand and manage the growth of this expenditure a significant supply chain management program was implemented. This was complemented by a series of technical initiatives focussed on grinding media specifications, quality management and the prediction of grinding media wear rate as a function of physical ore characteristics. This paper discusses the methodology and outcomes of these activities.

Jan 1, 2012

By R. E. Dye

Introduction Research concerning all phases of hoisting practice, but more particularly the causes and prevention of hoisting rope deterioration and the improvement of safety dogs 158 for shaft conveyances, has been carried on intensively for the past three years in the Province of Ontario. Prior to the hoisting accident at the Paymaster mine on February 2nd, 1945, there had been no fatalities in the Province due to a hoisting rope failure. It was probably on this account that little original research on hoisting problems had been undertaken here and that the mining industry had been content to look to British, South African, and United States investigators for new developments in this field. Except for the Paymaster accident this might still be the case since, in any industry, it is apparently necessary for a serious accident to occur before any extensive programme of preventive research is launched. When this accident occurred, the Government of Ontario, with the close co-operation of the Paymaster officials and the mining industry as a whole, took immediate steps to determine the cause. A five-man, non-industry committee, selected from the Faculty of the University of Toronto with Dean C. R. Young as Chairman, was appointed by the Government, and a three-man Committee consisting of R. D. Parker, General Superintendent of the International Nickel Company of Canada, Limited, R. L. Healy, General Manager of Wright Hargreaves Mines, Limited, and R. E. Dye, General Manager of Dome Mines, Limited, with the latter acting as Chairman, was appointed by the Ontario Mining Association.

Jan 1, 1948